Leaf essential oil compositions of Rudbeckia fulgida Aiton, Rudbeckia hirta L., and Symphyotrichum novae-angliae (L.) G.L. Nesom (Asteraceae)

Abstract

leaf essential oils from three herbaceous members of the Asteraceae, Rudbeckia fulgida, Rudbeckia hirta, and Symphyotrichum novae-angliae, were obtained by hydrodistillation and analyzed by gas chromatography - mass spectrometry. The leaf oils were dominated by sesquiterpene hydrocarbons, mainly (E)-caryophyllene (10.0%, 4.7%, and 4.4%, respectively), γ-muurolene (8.9%, 8.1%, and 5.4%, respectively), germacrene D (30.1%, 23.6%, and 25.5%, respectively), and δ-cadinene (17.8%, 16.2%, and 14.3%, respectively). Additionally, (2E)-hexenal (6.0%, 20.2%, and 31.0%, respectively) was also abundant in the leaf oils. The essential oils were screened for antimicrobial activity, but were found to be inactive.